Remove SES submission queue

Amazon SES doesn't queue messages for you--it will attempt to deliver every message that was sent to its API. However, it looks like Mautic does have some queuing functionality.

As a short term approach, I recommend that you disassociate Mautic from your verified domain to prevent further damage to your domain's reputation. You should also change passwords for all IAM credentials that have the ability to send through SES or that were associated with Mautic in any way, and of course change your Mautic passwords (and set up two-factor authentication for all users, if Mautic offers that feature).